A News of the World lawyer ordered surveillance of two solicitors engaged in litigation against the paper for phone hacking in order to gain an improper advantage, a disciplinary tribunal has heard.

Tom Crone, legal affairs manager with the now defunct newspaper’s publisher, News International (now News UK), is accused of attempting to uncover an alleged affair between the two colleagues to provide the NoW with “good leverage” in legal proceedings.

The Bar Standards Board has brought six charges of professional misconduct against him, which, if proved, could lead to him being disbarred. He denies the charges.

At Tuesday’s hearing of the tribunal in central London, prosecuting counsel Christopher Aylwin, told the five-person panel that Crone asked the paper’s newsdesk to put solicitors Mark Lewis and Charlotte Harris under surveillance in order to find out information that could embarrass the pair.

“It was your intention to use evidence of the affair, if you’d got it, to persuade – and I use the word neutrally – to pressure Miss Harris and Mr Lewis,” said Aylwin, cross-examining Crone. “You were looking for an excuse to embarrass them in their private lives. You would not have used a bare-faced threat – you’re far too aware of the consequences to have done that – but there are ways of getting your point across, are there not?”

Crone admits requesting that the solicitors, then both at Manchester firm George Davies (now part of Mills and Reeve), be placed under surveillance but denies the charge that it was aimed at getting advantage by improper means.

The surveillance found no evidence of an affair.

Crone claims that he acted because of concerns that the pair were leaking confidential legal information to the Guardian and exchanging confidential information relating to different phone-hacking claims they were working on when they should not have been.

Among the cases Lewis worked on was the claim by then Professional Football Association boss Gordon Taylor, which was cited in the initial Guardian revelations about the phone-hacking scandal.

Crone told the panel that if Lewis and Harris were having an affair it would have provided circumstantial evidence that they were passing confidential information between each other. The intention would then be to report them to the Solicitors Regulation Authority (SRA), alleging that they had breached professional standards, he said.

But Aylwin said Crone’s intention was “to obtain good leverage. It wasn’t anything to do with recusal or claims to the SRA, it was to have your way as far as the litigation was concerned.”

Crone, who often expressed irritation at the questioning, replied: “No, that was absolutely not the case.” He added: “I would regard that as a clear blackmail threat which I wouldn’t make. I wouldn’t dream of doing that.”

He said that any such threat would have been futile against experienced solicitors such as Lewis and Harris, who would have simply rung the police.

Crone joined Rupert Murdoch’s UK newspaper division in 1985, acting for both the NoW and the Sun. He resigned in July 2011, the month in which the NoW was closed.

In 2007, after the jailing of the NoW’s royal editor, Clive Goodman, he supervised an internal investigation into hacking at the paper but could find no evidence to suggest anyone else was involved.

Crone gave evidence to the Commons culture, media and sport select committee about hacking allegations and also to the Leveson inquiry.

He was arrested in August 2012 in connection with the Metropolitan police’s investigation into hacking but in October 2014, the Crown Prosecution Service announced he would not face charges because there was “insufficient evidence for a realistic prospect of conviction”.

Among those watching proceedings was Formula one boss Max Mosley who, in 2008, when Crone was still at News International, won £60,000 in a privacy action against NoW after the Sunday tabloid falsely accused him of taking part in a “sick Nazi orgy”.